Laboratory model of adaptive radiation: A selection experiment in the bank vole

In a laboratory colony of a wild rodent, the bank vole Myodes (= Clethrionomys) glareolus, a multiway artificial selection experiment was applied to mimic evolution toward high aerobic metabolism achieved during locomotor activity, predatory behavior, and ability to cope with herbivorous diet. Four lines for each of the selection directions and four unselected control lines have been maintained. After three generations of within-family selection, the maximum rate of oxygen consumption achieved during swimming was 15% higher in the selected than in the control lines (least square means, adjusted for body mass: 252.0 vs. 218.6 mL O-2/h, P = 0.0001). When fed a low-quality diet made of dried grass, voles from the lines selected for ability to cope with herbivorous diet lost about 0.7 g less mass than voles from the control lines (-2.44 vs. -3.16 g/4 d, P = 0.008). In lines selected for predatory behavior toward crickets, proportion of predatory individuals was higher than in the control lines (43.6% vs. 24.9%; P= 0.045), but time to cap ture calculated for the successful trials did not differ between the lines. The experiment continues, and the selected lines of voles will provide a unique model for testing hypotheses concerning correlated evolution of complex traits.